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Full text of "Practical Organic Chemistry"

96                 PRACTICAL ORGANIC CHEMISTRY

dissolved in 12 c.c. of water heated on the water-bath. A
vigorous reaction occurs and yellow crystals of sodium bis-
diazoacetate are deposited. Cool, add 10 c.c. of spirit, and
filter and wash with spirit.

N = N\

>CH COONa

See Appendix ; p. 255.

PREPARATION 22.

Diethyl Malonate.

Conrad, Annalen, 1880, 204, 126; W. A. Noyes, Amer.
Chem.J.) 1896, 18, 1105.
50 grms. chloracetic acid (in 100 c.c. water)
40         potassium carbonate
40     35    potassium cyanide (in powder)
The solution of chloracetic acid is poured into a wide basin
(20 cm. diam.), and whilst the mixture is heated to 55  60
potassium carbonate (40 grms.) is added until the evolution of
carbon dioxide ceases and the liquid is neutral. A solution of
potassium chloracetate is thus obtained. Potassium cyanide
(40 grms,) is now added and well stirred.* When the first
reaction is over, the contents of the basin are cautiously heated
on 'the sand-bath, whilst the mass is continuously stirred with a
thermometer until the temperature reaches 135. The brown
semi-fluid mass is allowed to cool and stirred whilst solidifying,
and then quickly broken up into coarse powder and introduced
into a round flask (J litre). The potassium cyanacetate which has
been formed is now converted into the ester, and at the same
time hydrolysed by boiling with sulphuric acid. Absolute
alcohol (20 c.c.) is gradually added with shaking, and the flask
is then mounted on a water-bath and attached to a reflux con-
denser. A cold mixture of 80 c.c. absolute alcohol and So c.c.
concentrated sulphuric acid are added in the course of about ten
minutes, and the flask heated for one hour on the water-bath.
The mixture is cooled quickly, 100 c.c. of water added, and any